Notes- Use of Acetone Dimethyl Acetal in Preparation of Methyl Esters

Lorette, N. B.; Brown, J

doi:10.1021/jo01084a633

Cited by 70 publications

(14 citation statements)

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“…The sluggish reaction observed (experiment 1) with low proportions of methanol is in agreement with the original observations of Lorette and Brown (27). T h e colors observed are indicative of the formation of polymers, probably from isopropenyl ether, although most authors cite DRIP as the origin (25,27,31). bye regard this as due simply to the lack of polar diluent for the concentrated acid.…”

Section: Resultssupporting

confidence: 89%

Ozonolysis of unsaturated fatty acids. II. Esterification of the total products from the oxidative decomposition of ozonides with 2,2-dimethoxypropane

Castell¹,

Ackman²

1967

Can. J. Chem.

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The total acidic products from the performic acid oxidation of the ozonide of methyl oleate formed in methanol may be esterified directly in a few hours with 2,2-dimethoxypropane. The ester concentrations are adequate for the determination of the positional isomers of monoethylenic fatty acids directly from the reaction mixture, using a hydrogen flame ionization +ps-liquid chromatography detector. Dimethyl sulfoxide was not required to prevent the breakdown of 2,2-dimethoxypropane under the conditions employed.

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Section: Resultssupporting

confidence: 89%

Ozonolysis of unsaturated fatty acids. II. Esterification of the total products from the oxidative decomposition of ozonides with 2,2-dimethoxypropane

Castell¹,

Ackman²

1967

Can. J. Chem.

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“…Because esterification reactions using alcohol (i.e. methanol, i / n ‐propanol) and acid (acetyl chloride) involve the elimination of water, 2,2‐dimethoxypropane is occasionally used as a water scavenger, by converting water into volatile methanol 33, 42. However, there exists the potential for this reagent to initiate other reactions, producing compounds which are difficult to eliminate during the work‐up step(s).…”

Section: Resultsmentioning

confidence: 99%

Optimisation of derivatisation procedures for the determination of δ¹³C values of amino acids by gas chromatography/combustion/isotope ratio mass spectrometry

Corr

Berstan

Evershed

2007

Rapid Comm Mass Spectrometry

134

145

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Compound-specific stable carbon isotope analysis of amino acids by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) is a highly selective and sensitive method for probing the biosynthetic/diagenetic pathways, pool size and turnover rates of proteins, previously intractable to bulk isotope analyses. However, amino acids are polyfunctional, non-volatile compounds which require derivatisation prior to GC analysis. While a wide range of derivatives exist for the GC analysis of amino acids only a handful have been utilised for their GC/C/IRMS analysis. Significantly, none of those derivatives currently employed appear completely satisfactory and a thorough assessment of their relative utility is lacking. Seven derivatives (three previously reported and four novel) for obtaining delta(13)C values of amino acids via GC/C/IRMS analysis were compared. More specifically, standard mixtures of 15 protein amino acids were converted into N-acetylmethyl (NACME) esters, N-acetyl n-propyl (NANP) esters, N-acetyl i-propyl (NAIP) esters, N-trifluoroacetyl-i-propyl (TFA-IP) esters, N-pivaloyl methyl (NPME) esters, N-pivaloyl n-propyl (NPNP) esters and N-pivaloyl i-propyl (NPIP) esters. Each derivative was assessed with respect to its applicability to carbon isotope determinations of all the common alpha-amino acids, reaction yield, chromatographic resolution, stability, analyte-to-derivative carbon ratio, kinetic isotope effects and errors associated with their carbon isotope determinations. The NACME derivative was concluded to be the preferred derivative mainly due to the highest analyte-to-derivative carbon ratio being achieved, resulting in the lowest analytical errors for amino acid delta(13)C value determinations, ranging from +/-0.6 per thousand for phenylalanine, leucine and isoleucine to +/-1.1 per thousand for serine and glycine.

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“…2,2-Dimethoxypropane (2,2-DMP) is used to facilitate the transesterification of triglycerides (28). Though 2,2-DMP itself is condensed to produce yellow polymer, and this by- product is detected on the chromatogram, the production could be inhibited by DMSO (29).…”

Section: Resultsmentioning

confidence: 99%

A recommended esterification method for gas chromatographic measurement of conjugated linoleic acid

Yamasaki

Kishihara

Ikeda

et al. 1999

J Americ Oil Chem Soc

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The effect of the methylation method on isomerization of conjugated linoleic acid (CLA) in gas chromatographic analysis was studied. Among methylation methods examined, the magnitude of isomerization of CLA was greatest with BF 3 catalyst, followed by HCl and H 2 SO 4 catalyst. Shorttime methylation did not extensively change the CLA composition in all methods, and c,t and t,c isomers were essentially maintained, while the appearance of t,t isomers and unknown peaks was practically restricted. After 120 min of methylation, there was essentially no conversion in the H 2 SO 4 method, in contrast to a marked change in the BF 3 method. The antioxidants butylated hydroxytoluene, ascorbic acid, β-carotene, and α-tocopherol did not suppress conversion, while dimethylsulfoxide (DMSO) and dimethylformamide (DMF) attenuated the changes in CLA composition. Suppression was more effective in the H 2 SO 4 method than in the BF 3 method. Thus, methylation with H 2 SO 4 in the presence of a proper amount of DMSO or DMF is recommended for esterification of CLA.Paper no. J9018 in JAOCS 76, 933-938 (August 1999).

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Notes- Use of Acetone Dimethyl Acetal in Preparation of Methyl Esters

Cited by 70 publications

References 1 publication

Ozonolysis of unsaturated fatty acids. II. Esterification of the total products from the oxidative decomposition of ozonides with 2,2-dimethoxypropane

Ozonolysis of unsaturated fatty acids. II. Esterification of the total products from the oxidative decomposition of ozonides with 2,2-dimethoxypropane

Optimisation of derivatisation procedures for the determination of δ¹³C values of amino acids by gas chromatography/combustion/isotope ratio mass spectrometry

A recommended esterification method for gas chromatographic measurement of conjugated linoleic acid

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Notes- Use of Acetone Dimethyl Acetal in Preparation of Methyl Esters

Cited by 70 publications

References 1 publication

Ozonolysis of unsaturated fatty acids. II. Esterification of the total products from the oxidative decomposition of ozonides with 2,2-dimethoxypropane

Ozonolysis of unsaturated fatty acids. II. Esterification of the total products from the oxidative decomposition of ozonides with 2,2-dimethoxypropane

Optimisation of derivatisation procedures for the determination of δ13C values of amino acids by gas chromatography/combustion/isotope ratio mass spectrometry

A recommended esterification method for gas chromatographic measurement of conjugated linoleic acid

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Optimisation of derivatisation procedures for the determination of δ¹³C values of amino acids by gas chromatography/combustion/isotope ratio mass spectrometry